1. Field of the Invention
The subject matter of the invention is a fuel delivery unit for delivering fuel from a fuel container to an internal combustion engine of a motor vehicle, comprising a flange for closing an opening in the fuel container, a splash pot which is connected to the flange by means of supporting elements, a fuel pump which is arranged in said splash pot, a fuel filter, a pressure regulator, a filling level sensor and a pump pre-filter, and means for connecting each individual component to a ground potential of the motor vehicle.
2. Description of the Related Art
Electrostatic charges may form in components which are situated in fuel or around or through which fuel flows. The formation of electrostatic charges depends on the electrical conductance of the fuel used, the external conditions, for example humidity, and the flow rate of the fuel around or through the corresponding component. Depending on the type and size of the electrostatic charge and the conditions inside the fuel container, for example oxygen content, there is a corresponding risk of electrostatic charges being reduced by means of a flashover. In a worst-case scenario, such a flashover can lead to ignition of the fuel mixture. In order to prevent flashovers, an attempt is made to reduce electrostatic charges before the flashover voltage is reached.
To this end, it is known to electrically conductively connect the corresponding component to the ground potential of the motor vehicle. This is achieved, in particular, by the component being connected directly to the ground potential. Therefore, in the case of a fuel pump, the electrical connection lines of said fuel pump are used to discharge electrostatic charges.
In the case of components without their own electrical connection lines, it is possible to discharge electrostatic charges by connecting the corresponding component to the ground potential of the motor vehicle directly via an electrical line. This manner of discharging electrostatic charges is particularly cost-intensive on account of the additional outlay on material, assembly and laying of the electrical line.
A further option is to electrically conductively connect the component to another component which has means for discharging electrostatic charges. Therefore, a pressure regulator can be electrically conductively formed with the metal housing of a fuel pump in order to discharge electrostatic charges. The electrically conductive connection can be an electrical line or a conductive material, for example metal or electrically conductive plastic. A critical disadvantage of this series connection of components which are electrically conductively connected to one another is that the risk of flashover greatly increases when the electrical connection to ground potential is interrupted. The reason for the greatly increased risk is that, on account of the interruption, the individual capacitances of the disconnected components add up to form a total capacitance.